Telephone system.



E. R. 001mm. TELEPHONE SYSTEM. APPLICATION FILED DEC. 26, 1906.

901,785. Patented Oct. 20, 1908.

ATTORNEY -n01s, have invented 'afcert'ain new. and useful to the accompanying drawi change system equipped in accordance with tions whereby, when the telephone receivers traced from the grounded battery 14, through UNITED sTAilts P igENT OFFICE. v

ELMER R. OORWIN, OF CHICAGO, ILLINOIS, ASSIGNOB TO ,GORWIN TELEPHONE MANUFAC- TURING GO., OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

TELEPHONE SYSTEM.

' Specification of Letters Patent.

Patented Oct. 20, 1908.

Application filed. December 26,1906. Serial No. 349,374.

To all whom it may concern:

Be it known that 'I, ELMER R. GORWIN,C11Z1- zen of the United States, residing at Chicago, in the county of Cook and State of Illi- Improvement in Telephone Systems; of which the followingi's a full, clear, concise, and exact description, reference being had ngs, forming a part of this specification.

I will explain my invention by reference to the accompanying drawing and will also set it forth in the claims. I

In the dr'awingis' shown a telephone exmy invention. V i

There are indicated two of many sub-sta-* tions, A, B, each, in the embodiment of the invention shown; having a transmitter 1, a receiver 2, a call bell 3, a switch-hook 4, a condenser 5, an impedance coil 6, together, with suitable contacts and circuit connec- 2 are upon their switch-hooks, the bells 3, together with the condensers 5, are bridged across the sides of the telephone lines'7, 8, and whereby, when the telephone receivers are removed from their hooks, the bridges including said signal bells are opened and thetransmitters are thrown into conductive connection with the lines, whereby battery may be fed therethrodgh through the impedance coil 6, and whereby telephone currents may be inr pressed upon the lines at the sub-stations at the transmitters or maybe received at the receivers. I do'not wish to be limited to the precise sub-station circuits indicated. The limbs 7 8 of "the telephone lines are connected with sleeve contacts or thimbles 9 and tip springs or contacts 10, respectively. The cpntactsxlO are normally in connection with back contacts, each backcontact constituting a terminal of a grounded conductor that includes the line lamp or signal device 12. Each springjack includes another line sprin 13in permanent electrical connection wit the corresponding sleeve 9 and normally in connection with a back contact that is grounded through a battery 14 common to the backcontacts of the springs 13; When a call is initiated, circuit is established through the line lamp 1 2 that may be signal controllin the spring1'3 and its back contact, the line limb .7 the impedance winding 6, the tele circuit, while the other sleeve contact constitutes a terminal of a conductor inclu ding a supervisory or clearing-out signal device 17 which is normally connected to ground when the armature of the associated supervisory relay 18.is unattracted.

hen the operator answers a call, she inserts one of the plugs into the jack of the calling subscriber, and thereby connects the supervisory signal device 17 corresponding with the calling subscribers line, Withthe battery 14:. Since the sleeve contacts of the inserted plug are adapted'to engage the elements 9 and 13 of the occupied jack, and as the elements 9 and 13 are permanently connected electrically, the supervisory device 17 is connected with the battery 14, as stated.

-The supervisory signal controlling devices 18 are included in bridge of the talking strands of the cord circuit, so thatwhen the telephonereceivers are removed from the switch-hooks at the subscribers stations, said devices or relays 1 8 are included in con uctively continuous paths established by reason of the impedance coils 6 and their connections, thereby then preventing the presentation of supervisory signals. 'When, however, a subscriber restores his telephone upon its hook, the conductively' continuous path afforded athis station by the impedance coil 6 and the connections thereof, is replaced by the signalbell branch includingt'he condenser 5, so 61511111116 corresponding relay=1-8 1s included in o en circuit, whereby its armature is allowe to fall back and-the corres onding supervisory slg nal device '17 is inc titled in a closed circult,

traced hitherto, and including the sleeves of the-correspondin plug and the contact elementS'eH'a nd' I3 0' the engaged jack.

Assuming that the system is equipped with-double supervision, as illustrated, the

operator, upon seeing both signals occasioned at oncebrought into communication with by two connected subscribers when they restore their telephones, withdraws the plugs from the jacks of said subscribers, and thereby opens the circuits of the signal devices 17, for the withdrawal of the plugs causes electrical disconnection between the sleeves thereof.

By sub-station I, of course, do not limit myself to a'subscribers telephone sub-station, since it is obvious that the invention resides in effecting control of the relay over a telephone line, whether or not said telephone line extends to a subscribers outfit.

The cord circuit herein illustrated is desirably symmetrical; that is, either plug may be used as an answering plug .or a connecting plug, and in connection with this characteristic, I provide apparatus for antomatically determining the relations of the operators telephone equipment with the cord circuit, so that no matter which plug is 'used by the operator as an answeringplug, the operator may have automatic connection of her telephone conductors eflected with.a calling telephone line, which connection is broken when the operator has connected two lines together. To this end, I desirably employ the instrumentalities illustrated.

I have shown condensers 19, 20 and 21, which, as it will appear by inspection of the diagram, cause separation between the circuits of the relays 18 and the relays 22, which latter relays take part in the control of the association of the'operators telephone equipment with the cord circuit. lay 22 is included in the same circuit with the associate signal device 17, so that whenever said signal device 17 is in circuit, the

corresponding relay 22 is in circuit and is energized, whereby the cord circuit is not rendered more complicated to se ure the results of my invention. The re ays 22 are also in the same bridges with the relays 18,

so'that the relay 22 corresponding to the plug used as an answering plug, is sure to be energized to attract its armature and disconnect the armature-switches 23, 24 from their contacts, said contacts 23, 24 constituting terminals of tap conductors or legs branched from the talking strands of the cord circuit, the armature-switches 23, 24 constituting terminals of the operators tele phone equipment, 25. As appears, there are two sets of switches 23, 24 with their associate contacts, bne'set being controlled by the relay 22 corresponding with an answering plug and the other set being controlled by the relay 22'corresponding with the plug used as a connecting plug, and though contact is broken at 23, 24 by reason of the energization of the relay 22 corresponding to the plug used as an answering plug, contact is not yet broken at 23, 24 respecting the companion relay 22 so that the operator is Each re the calling ,party, the subscriber or other party, by reason of the contact maintained at the contacts 23, 24 associated with the plug then used as a connecting plug. The contacts 23, 24 of one set are multiply re- .lated with the contacts 23,- 24 of the other set; that is, the 'operators telephone equipment has two sets of termi-nals'multiply related, each set including a pair of contacts 23, 24.

When the plug used as a connecting plug is inserted in the jack of the called subscriber, a local circuit is established for the associate relay 22, which may be traced from the groundedbattery '14, through the said relay 22 in question, thesleeves of the plug used as a connecting plug now electrically connected, the associate supervisory lamp 17, toground, whereby the operators telephone set is automatically excluded from connection with the cord circuit.

It will be seen that the control of the opera-tors telephone outfit herein described, is bad whether either plug is used as an answering plug or a connecting plug.

Itwill be seen that the plugs cooperate with the jacks in establishing local circuits for the relays 22, and that these circuits are initially local at the connecting 0nd of the cord circuit and are thereafter maintained over the line when the called subscriber responds, for then the local-circuit is opened at the contact of the associate Ealled subscribers supervisory relay 18.

It will be noted that the called subscriber has no control over the relay 22 associated with his line, to the extent of changing the operated condition of said relay, but that such control is exercised only at the exchange by a calling plug and the engaged jack.

While I have herein shown and particularly described the preferred embodiment of my invention, I do not wish to be limited to the precise embodiment herein set forth, but, Having thus described my invention, I

claim as new and desire to secure by Letters- Patent the following 1. A telephone exchange system including telephone lines, jacks therefor; a cord circuit.- for uniting telephone lines in conversation, an operators telephone equipment having multiplied terminals, and two relays, one serving to control tne connection of one set of said multiple terminals with'the cord circuit and the other serving to control the connection of the other set of saidmultiple terminals with the cord circuit, one of said relays being controlled by the plug used as an answering plug and apparatus associated with the line connected with the said answering,plug,'whi1e the other relay is controlled .by the plug used as a connecting plug and apparatus associated with the line connected with the said connecting plug.

' telephone lines, jacks therefor, a cord circuitfor uniting telephone lines 1n conversation,

2. A telephone exchange system including telephone lines, jacks therefor, a cord circuit for uniting tele hone lines in conversation, an operators te ephone'equipment, and two relays, each serving to establish connection of the operators equipment with the cord circuit, and each adapted to breakthe con nection it efiects, one of said relays being controlled by the plug useetas an answering.

plug and apparatus associated with the line connected with the said answering plug,

while the other relay is controlled by the plug used as a connecting plug and apparatus associated with the line connected with the said connecting plug.

3. A telephone exchange system including an operators telephone equipment having multiplied terminals, and two relays, one serving to control the-connection of one set of said multiple terminals with the cord circuit and the other serving to control the connection of the other set of said multiple terminals with the cord circuit, one of said relays being controlled by the plug used as an answering plug and apparatus associated with the line connected with the said answering plug, While the other relay is controlled by the plug used as a connecting plug and apparatus associated with theline connected with the said connecting plug, tlie'relayassooiated with the plug used as an answering effects, while the relay associated with the plug used as a connecting plug maintains the connection it governs until said connecting plug has been connected with the called line.

4. A telephone exchange system including telephone lines, jacks therefor, a cord circuit for uniting telephone lines in conversation, an operators telephone equipment, and two relays, each serving to establish connection of the operators equipment with the cord circuit, and each adapted to break the con nection it effects, one ofsaid-relays being controlled by the plug used as an answering plug and apparatus associated with the line connected with the said answering plug, While the other relay is controlled by the plug used as a connecting plug and apparatus associated with the line connected with the said connecting plug, the relay associated with the plug used as an answering plug serving to break the connection it eflects, while the relay associated with the plug used as a connecting plug maintains .the connection it governs until said connecting plug has been connected with the called line.

In witness whereof, I hereunto. subscribe my name this 22nd day of December A. 1).,

ELMER R. COR-WIN. \Vitncsses (i. L. GRAGG, Leon (1. S'L'ROIL 

